To me it seams that DIMM socket #1 is defective, because after swapping the DIMM modules still only DIMM2 is detected. Which is the same situation as before swapping the DIMM modules.
Do you mean with "DIMM2" is defective, that:
a.) the Crucial DIMM module is defective
or
b.) that the Intel DIMM socket #2 is defective?